Cooling device for mercury-arc lamp or the like

ABSTRACT

A cooling device for a mercury-arc lamp having a housing, an inlet nozzle for introducing cooling water into the housing, a mercury-arc lamp, an exhaust port for discharging the cooling water from the housing, a conduit communicating with the exhaust port and containing the lamp, and a transparent window for directing light of the lamp to the outside. The inlet nozzle jets the cooling water in the vicinity of the window.

United States Patent [72] Inventors ,IiroDegawa Chiba-ken;

Osamu Takeuclli, Tokyo, both of, Japan [21] AppLNo. 836,868

[22] Filed June 26, 1969 [45] Patented Sept. 7, 1971 [73] Assignee Sony Corporation Tokyo, Japan [32] Priority June 29, 1968 [$4] COOLING DEVICE FOR MERCURY-ARC LAMP OR THE LIKE 8 Claims, 6 Drawing Figs.

[52] U.S. Cl 313/24, 313/35, 313/36 [51] Int. Cl H01] 7/26 [50] Field of Search 313/24, 35, 36

[56] References Cited UNITED STATES PATENTS 2,275,739 3/1942 Dellian et al 313/2 4 X 2,295,031 9/1942 Davis 313/24 X 2,295,046 9/1942 Noel 313/24 X Primary Examiner-Roy Lake Assistant ExaminerDarwin R. Hostetter Attorney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: A cooling device fora mercury-arc lamp having a housing, an inlet nozzle for introducing cooling water into the housing, a mercury-arc lamp, an exhaust port for discharging the cooling water from the housing, a conduit communicating with the exhaust port and containing the lamp, and a transparent window for directing light of the lamp to the outside. The inlet nozzle jets the cooling water in the vicinity of the window,

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JIRO DEGAWA .1 l osAmu TAKEUCHI BYMMM A! TURN/5 YS COOLING DEVICE FOR MERCURY-ARC LAMP OR THE LIKE This invention relates to a cooling device for mercury-arc lamps or the like, and more particularly to a water-cooling device for a line source of light.

A light source of high brightness is required for the making of color picture tubes. For this purpose, a mercury-arc lamp is widely used but it necessitates the use of cooling means when high brightness is desired. The cooling method is generally divided into air-cooling and water-cooling. The water-cooling is high in cooling efficiency but presents problems such as complicated construction of the cooling device, much trouble for replacement of the light source and nonuniformity in light density caused by air bubbles in-the cooling water lying on the surface of the mercury-arc lamp and a window glass of lighting window of the cooling water tank. Bubbles are formed in the cooling water when it is. heated which interfere with the light source.

Further, the cooling device requires a window of, for example, glass which permits the passage of light emitted from the mercury-arc lamp therethrough and total reflection of light occurs at the window and this causes loss of light. The different indexes of refraction of water, glass and air, causes the light energy to be shifted in direction.

The present invention has for its object the elimination of the defects experienced in the prior art by constructing the cooling device insuch a manner as to increase the velocity of flow of the cooling water and prevent bubbles in the light source portion of the device. Namely, the cooling device is designedsothat the cooling water from a nozzle communicating witheaninlet port directly flows past the window portion to sweepaway the air bubbles in the cooling water from the window.

Accordingly, it is one object of this invention to provide a cooling, device for mercury-arc lamps or the like which prevents the occurrence of nonuniform in light density.

It is another object of this invention to provide a cooling device which makes it easy to replace a lamp of the light source.

Itis stilltanother object of this invention to provide a cooling devicewhich decreases loss of light and does not shift the effectivepositionof thelight source.

Other objects, features andadvantages of this invention will becomeapparent from the following description taken in conjunction-with the accompanying drawings, in which;

FIG. 1 is a schematic diagram showing the manner of optical printing for the making of a color phosphor screen, for explaining this invention;

FIG. 2 is a schematic diagram showing a conventional cooling device for a mercury-arc lamp, for explaining this invention;

FIG. 3 is a top. plan view, partly in cross section, showing one example of a cooling device for a mercury-arc lamp or the like produced according to this invention;

FIG. 4 is a side view of the cooling device exemplified in FIG. 3; and

FIGS-5 and 6 are cross-sectional views taken along the lines VV and VI-VI in FIG. 3 respectively. In Chromatron (Registered Trademark) or Trinitron (Registered Trademark) color picture tubes a grid device, which consists of many parallel grid elementssuch as metal wires or strips stretched in one direction at predetermined intervals, is disposed opposite thecolor phosphor screen and an electron beam is directed to the phosphor screen through the grid elements and impinges upon the screen at a predetermined location corresponding to a particular color.

The phosphor screen of the color picture tube of such construction is made up of a plurality of phosphor strips respectively emitting red, green and blue colored energy which are sequentially arranged in a repeating cyclic order.

For the making of such a phosphor screen consisting of the phosphor strips as described above, it is preferred to employ an optical printing method such that phosphors are sequentially coated by the use of an optical mask or a grid itself having a predetermined pattern.

Referring to FIG. 1, the optical printing method will be briefly described. Namely, a phosphor slurry 2 formed of, for example, a red color emissive phosphor and a photosensitive binder is coated on the entire interior surface of a panel 1 of the tube envelope of a color picture tube on which a color phosphor screen is desired to be formed. An optical mask 3, which has an optical pattern corresponding to the pattern of the red phosphor strips of the color phosphor screen which will be ultimately produced, is placed in opposing relation to the. panel 1 and a light source 4 is disposed behind the optical mask 3.

Then, the phosphor slurry 2 laid down on the interior surface of the panel 1 is exposed through the optical mask 3 to irradiation by light from the light source 4 to form in the slurry a latent image of the optical pattern on the mask 3, after which the interior surface of the panel 1 is subjected to a developing process to provide red color phosphor strips of a predetermined pattern. These processes are similarly repeated in connection with phosphors of other colors, for example, green and blue color emissive phosphors until an entire phosphor screen is formed on the panel 1.

In this case the light source 4 is usually a mercury-arc lamp. The light source 4 is preferred to be a linear light source, extending in the lengthwise direction of the phosphor strips which will be ultimately formed so as to ensure uniform exposure of the phosphor strips to light over their entire length.

However, a mercury-arc lamp, whichhas a linear luminous portion and high brightness, is small in tube diameter, which leads to an increase in the heating value per unit area of the tube surface, and hence necessitates effective heat radiation on the tube surface. Water-cooling methods are regarded as effective for efficient heat radiation. In the watercooling method, however, air is always contained inthe cooling water and generates bubbles, which-lie on the surface of the mercury-arc lamp or the window glass of a lighting window of the cooling device. Since air in the cooling water expands by heat of the mercury-arc lamp, the bubbles collect together and grow large. Accordingly, if the bubbles lie on the surface of the mercury-arc lamp, cooling is not effectively achieved on those areas of the surface of the lamp where the bubbles stay, and heat radiation is interrupted by the air in the bubbles. As a result of this, heat generated by the mercury-arc lamp is not effectively radiated and the tube of the lamp is locally heated up to a high temperature, which leads to distortion of the tube and finally to explosion thereof. Further, the bubbles on the glass window cause light of the lamp to be refracted by the bubbles to cause nonuniformity in the light density. The use of such a mercury-arc lamp for the optical printing of the color phosphor screen will result in nonuniformity of printing. In the case where the window is located on the upper edge of the heated cooling tank, the bubbles rise and stay on the window, so that the above drawback becomes more noticeable.

In usual cooling devices the window glass 9 of a cooling tank 8, which has disposed thereina mercury-arc lamp 4 and is hollow so that a cooling water may pass therethrough, and is formed with a plate glass, as shown in FIG. 2. Accordingly, in such structure rays of light 10 from the mercury-arc lamp 4 are refracted by the plate glass 9 as indicated in full line, so that a virtual light source 12 is produced in front of the light source 4 when viewed from a plane 11 irradiated by light.

While, in the case of the optical printing for the making of the color phosphor screen, the light source 4 is located, for example, at the position of deflection center of an electron beam, and consequently the use of a light source equipped with such a cooling device such as shown in FIG. 2 leads to drawbacks such as difficulty in positioning of the light source and nonuniformity of the light density.

Further, total reflection occurs on the interior surface of the glass plate 9 at that area where the incidence angle of light from the light source 4 is great, thus causing a decrease in the effective light directed to the plane 11.

FIGS. 3 to 6, inclusive, illustrate one example of the device of this invention which is free from the defects experienced in the prior art. Reference numeral indicates a cooling tank, which has a tubular hollow opening 20c with its axis XX substantially in a horizontal direction and in which a light source, for example, a mercury-arc lamp 4 is placed.

Substantially at the center in the opening 200 of the cooling tank 20, there is disposed along the axis XX a cylindrical cooling water conduit 21 formed of a transparent material such as quartz glass with a uniform thickness in which the light source 4 is placed. A lighting window 22 is provided on the upper side of the cooling tank 20 at a position opposite the light source 4 and a cylindrical transparent window glass 23, which is formed of, for example, quartz glass or the like and has a uniform thickness, is sealed to the window 22 about the axis XX in a watertight manner by the use of packings 24. Reference numeral 25 designates supports for the window glass 23. In the tank 20 there are provided an inlet port 26 for introducing the cooling water into the room 20c and an exhaust port 27 for discharging the cooling water from the tank 20. It is preferred to locate the inlet port 26 and the exhaust port 27 on one side 20a of the tank 20. Further, the exhaust port 27 is positioned on the lower side of the tank 20, especially below the conduit 21.

In the vicinity of the peak of the cylindrical surface of the transparent window glass 23 there is provided on the side 20a of the opening 20c of the tank 20 a nozzle 28 which opens in the direction of the axis XX, communicates with the cooling water inlet port 26 and jets along the transparent window glass 23 the cooling water supplied from the inlet port 26.

The exhaust port 27 communicates with the conduit 21 at one end 21a. For the communication of the inlet port 26 with the nozzle 28 and the one end 210 of the conduit 21 with the exhaust port 27, a hollow tubular member 29, which has a passage 29a communicating with the end 21a of the conduit 21 in a watertight manner, is provided on the end portion 20a of the tank 20 along the axis XX and circular grooves 30 and 31 are provided at positions opposite the inlet port 26 and the exhaust port 27 on the periphery of the tubular member 29. The circular grooves 30 and 31 are isolated from each other in a watertight manner in cooperation with the inner wall of the cooling tank 20 and are isolated from the opening 20a of the tank 20. Reference numerals 32 and 33 indicate circular packings for isolating the circular grooves 30 and 31 from each other and the circular groove 31 from the opening 200 of the tank 20 in a watertight manner. Further, the circular groove 30 communicates with the cooling water inlet port 26 and the nozzle 28. An aperture 34 is formed in the tubular member 29 and communicates with the circular groove 31. The other end 21b of the conduit 21 opens into the opening 20c of the cooling tank 20. Then, a light source, that may be a mercury-arc lamp 4 to be cooled is placed in the conduit 21 along the axis XX thereof. Electrode terminals 4a and 4b at both ends of the mercury-arc lamp 4 are electrically led out to both ends 20a and 20b of the tank 20 and means is provided for mechanically supporting the mercury-arc lamp 4. For supporting the mercury-arc lamp 4, a conductive rod 35 is inserted into the hollow tubular member 29 to engage its top end with the terminal 4a and a conductive setscrew 37 is screwed into the head of the conductive rod 35 through a conductive spring 36 to hold the conductive rod 35 in resilient abutment with the terminal 4a at all times. The setscrew 37 is used as an external terminal on the ground side. While, the other terminal 4b of the mercury-arc lamp 4 is led out through an aperture bored in the end portion 20b of the tank 20 and is connected to a connector 38 to electrically lead the terminal 4b out of the tank 20. The terminal 411 of the mercury-arc lamp 4 is covered with an insulating tube 39 at least over that portion which is inserted into the tank 20. The insulating tube 39 is provided by a flange 39a, which is engaged with a stepped portion 400 fonned in the aperture 40 through a circular packing 41, and a cylindrical member 42 is screwed into the aperture 40 having screw threads for supporting the mercury-arc lamp 4 in position.

With the above arrangement, the cooling water is supplied through the cooling water inlet port 26. Thus, the cooling water supplied through the inlet port 26 is jetted from the nozzle 28 through the circular groove 30 as indicated by arrows in H6. 5 and the jetted water flows along the interior surface of the window glass 23 from one side 20a of the tank 20 to the other side 20b, so that even if bubbles lie on the window glass 23, they are swept away. Then, the cooling water flows into the conduit 21 through its open end 21b and flows on the mercury-arc lamp 4, thereafter being discharged through the hollow tubular member 29, the aperture 34 and the exhaust port 27.

With the above arrangement, the transparent window glass 23 is formed to be a cylindrical plane of substantially uniform thickness substantially about the axis XX, that is, about the mercury-arc lamp 4, so that light emitted from the mercuryarc lamp 4 is not refracted by the window glass 23 moves undeflected to irradiate the screen, and thus avoids the formation of a virtual light source and nonuniformity in light density.

Since the nozzle 28 is located at a position adjacent the window glass 23, bubbles can be swept away from the window glass 23 and even in the case where the lighting window is provided on the upper side of the tank the bubbles can be prevented from lying on the window glass, so that nonuniformity in the density of the irradiation light mentioned at the beginning of the specification can be avoided.

Further, since the mercury-arc lamp 4 to be cooled is placed in the conduit 21, the cooling water can be caused to flow at a high rate, so that the radiation on the surface of the mercuryarc lamp 4 can be efficiently achieved and bubbles lying on the surface of the lamp 4 can be effectively swept away. This prevents explosion of the mercury-arc lamp due to local temperature rise and nonuniformity in the intensity of illumination due to the bubbles.

in addition, since the exhaust port 27 is provided at a position lower than the conduit 21, replacement of the mercuryarc lamp 4 can be achieved with ease in the following manner. Namely, the cooling water is completely drained out of the conduit 21 by stopping introduction of the cooling water from the inlet port 26 and by discharging the cooling water in the tank 20 from the exhaust port 27, so that removal of the tubular member 42 allows replacement of the mercury-arc lamp 4 without causing any leaking of the cooling water.

It will be apparent that many modifications and variations may be effected without departing from the scope of the novel concepts of this invention.

We claim:

1. A light source for producing a fan-shaped beam of light comprising a housing,

a light source lamp mounted within said housing,

a conduit having at least one portion which is transparent attached to said housing and surrounding said light source lamp,

a transparent window mounted in said housing and in alignment with said transparent portion of said conduit for directing a beam of light from said lamp outside said housing,

an inlet port for introducing cooling fluid into said housing,

an exhaust port for discharging cooling fluid from said houssaid ixhaust port connected to said conduit,

a nozzle mounted within said housing and communicating with the inlet port and said nozzle positioned to locally direct cooling fluid onto the window formed in said housing, and

said conduit formed with an opening for receiving said cooling fluid after it has been directed past said window to direct the cooling fluid over said light source lamp to said exhaust port.

2. A device according to claim 1 wherein said housing is mounted such that the window is on the upper portion of said housing.

3. A device according to claim 2 wherein said nozzle is mounted at a location above said exhaust port.

4. A cooling device as claimed in claim 1 wherein the light source lamp is a mercury-arc lamp.

5. A cooling device as claimed in claim 4 which includes a T 4 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 827 Dated September 7, 1971 Inventor(s) JIRO DEGAWA and OSAMU TAKEUCHI It is certified that error a ppears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 61, should read --cooling tank, the heated bubbles rise and stay on the window,

Column 4, line 1, should read --39 is provided by a flange 39a,

which is engaged by a Signed and sealed this 18th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR.

ROBERT GOT'I'SCHALK Attesting Officer Commissioner of Patents RM PO-105U (10-69) USCOMM-DC B0376-PGD LLS GOVEFINMINT PRINYING OFFICE ID! O38SL\l 

1. A light source for producing a fan-shaped beam of light comprising a housing, a light source lamp mounted within said housing, a conduit having at least one portion which is transparent attached to said housing and surrounding said light source lamp, a transparent window mounted in said housing and in alignment with said transparent portion of said conduit for directing a beam of light from said lamp outside said housing, an inlet port for introducing cooling fluid into said housing, an exhaust port for discharging cooling fluid from said housing, said exhaust port connected to said conduit, a nozzle mounted within said housing and communicating with the inlet port and said nozzle positioned to locally direct cooling fluid onto the window formed in said housing, and said conduit formed with an opening for receiving said cooling fluid after it has been directed past said window to direct the cooling fluid over said light source lamp to said exhaust port.
 2. A device according to claim 1 wherein said housing is mounted such that the window is on the upper portion of said housing.
 3. A device according to claim 2 wherein said nozzle is mounted at a location above said exhaust port.
 4. A cooling device as claimed in claim 1 wherein the light source lamp is a mercury-arc lamp.
 5. A cooling device as claimed in claim 4 which includes means for supporting the mercury-arc lamp on both ends thereof.
 6. A cooling device as claimed in claim 5 which includes a screw for securing one of the support means to the housing.
 7. A cooling device as claimed in claim 6 wherein removal of the one support means permits removal of the mercury-arc lamp.
 8. A cooling device as claimed in claim 1 wherein the window is cylindrical in shape and is arranged parallel to the length of the light source lamp. 